"are often exploited to make cast iron cookware and disc brake rotors. A typical chemical composition to obtain a graphitic microstructure is 2.5 to 4.0% carbon and 1 to 3% silicon by weight. Graphite may occupy 6 to 10% of the volume of grey iron. Silicon is important for making grey iron as opposed to white cast iron, because silicon is a ""graphite stabilizing"" element in cast iron, which means it helps the alloy produce graphite instead of iron carbides; at 3% silicon almost no carbon is held in chemical form as iron carbide. Another factor affecting graphitization is the"
"Graphene Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It is a semimetal with small overlap between the valence and the conduction bands (zero bandgap material).<ref name=""10.1002/adma.201502544 p.6519-6525""></ref> It is the basic structural element of many other allotropes of carbon, such as graphite, diamond, charcoal, carbon nanotubes and fullerenes. Graphene has many uncommon properties. It is the strongest material ever tested, conducts heat and electricity efficiently, and is nearly transparent. Graphene shows a large and nonlinear diamagnetism, greater than that of graphite, and can be levitated by neodymium"
"graphene proceeded rapidly once commercial scale production was demonstrated. By 2017, 13 years after creation of the first laboratory graphene electronic device, an integrated graphene electronics chip was produced commercially and marketed to pharmaceutical researchers by Nanomedical Diagnostics in San Diego. Graphene Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It is a semimetal with small overlap between the valence and the conduction bands (zero bandgap material).<ref name=""10.1002/adma.201502544 p.6519-6525""></ref> It is the basic structural element of many other allotropes of carbon, such as graphite, diamond, charcoal, carbon nanotubes"
"Graphene chemistry Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. The onset temperature of reaction between the basal plane of single-layer graphene and oxygen gas is below . Graphene combusts at . Graphene is commonly modified with oxygen- and nitrogen-containing functional groups and analyzed by infrared spectroscopy and X-ray photoelectron"
"that diamond is so strong. Although graphite is the most stable allotrope of carbon under standard laboratory conditions (273 or 298 K, 1 atm), a recent computational study indicated that under idealized conditions (""T"" = 0, ""p"" = 0), diamond is the most stable allotrope by 1.1 kJ/mol compared to graphite. Graphite, named by Abraham Gottlob Werner in 1789, from the Greek γράφειν (""graphein"", ""to draw/write"", for its use in pencils) is one of the most common allotropes of carbon. Unlike diamond, graphite is an electrical conductor. Thus, it can be used in, for instance, electrical arc lamp electrodes. Likewise,"
"exploded or low- to intermediate-sized stars expelled their outer envelopes late in their lives. Graphite may be the second or third oldest mineral in the Universe. Graphite has a layered, planar structure. The individual layers are called graphene. In each layer, the carbon atoms are arranged in a honeycomb lattice with separation of 0.142 nm, and the distance between planes is 0.335 nm. Atoms in the plane are bonded covalently, with only three of the four potential bonding sites satisfied. The fourth electron is free to migrate in the plane, making graphite electrically conductive. However, it does not conduct in"
"Graphane Graphane is a two-dimensional polymer of carbon and hydrogen with the formula unit (CH) where ""n"" is large. Graphane should not be confused with graphene, a two-dimensional form of carbon alone. Graphane is a form of hydrogenated graphene. Graphane's carbon bonds are in ""sp"" configuration, as opposed to graphene's ""sp"" bond configuration, thus graphane is a two-dimensional analog of cubic diamond. The structure was found, using a cluster expansion method, as the most stable of all the possible hydrogenation ratios of graphene in 2003. In 2007, researchers found that the compound is more stable than other compounds containing carbon"
"Graphyne Graphyne is a theorized allotrope of carbon. Its structure is one-atom-thick planar sheets of sp and sp-bonded carbon atoms arranged in crystal lattice. It can be seen as a lattice of benzene rings connected by acetylene bonds. Depending on the content of acetylene groups, graphyne can be considered a mixed hybridization, sp, where 1 < n < 2, and thus differs from the hybridization of graphene (considered pure sp) and diamond (pure sp). The existence of graphyne was conjectured before 1960, and attracted attention after the discovery of fullerenes. Although not yet synthesized, periodic graphyne structures and their boron"
"a streak on paper (hence its name, from the Greek verb ""γράφειν"" which means ""to write""), while diamond is the hardest naturally occurring material known. Graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials. All carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form at standard temperature and pressure. They are chemically resistant and require high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is"
"and Sn) nanosheets present properties similar to graphane. This compound has been proposed for hydrogen storage. Hydrogenation decreases the dependence of the lattice constant on temperature, which indicates a possible application in precision instruments. Graphane Graphane is a two-dimensional polymer of carbon and hydrogen with the formula unit (CH) where ""n"" is large. Graphane should not be confused with graphene, a two-dimensional form of carbon alone. Graphane is a form of hydrogenated graphene. Graphane's carbon bonds are in ""sp"" configuration, as opposed to graphene's ""sp"" bond configuration, thus graphane is a two-dimensional analog of cubic diamond. The structure was found,"
"Graphite, the standard state of carbon, has a lustrous appearance and is a fairly good electrical conductor. The diamond allotrope of carbon is clearly nonmetallic, however, being translucent and having a relatively poor electrical conductivity. Carbon is also known in several other allotropic forms, including semiconducting buckminsterfullerene (C). Nitrogen can form gaseous tetranitrogen (N), an unstable polyatomic molecule with a lifetime of about one microsecond. Oxygen is a diatomic molecule in its standard state; it also exists as ozone (O), an unstable nonmetallic allotrope with a half-life of around half an hour. Phosphorus, uniquely, exists in several allotropic forms that"
"Nephrite Nephrite is a variety of the calcium, magnesium, and iron-rich amphibole minerals tremolite or actinolite (aggregates of which also make up one form of asbestos). The chemical formula for nephrite is Ca(Mg, Fe)SiO(OH). It is one of two different mineral species called jade. The other mineral species known as jade is jadeite, which is a variety of pyroxene. While nephrite jade possesses mainly grays and greens (and occasionally yellows, browns or whites), jadeite jade, which is rarer, can also contain blacks, reds, pinks and violets. Nephrite jade is an ornamental stone used in carvings, beads, or cabochon cut gemstones."
"nickel ions can be coordinated with graphene ligands. Graphene chemistry Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity. The onset temperature of reaction between the basal plane of single-layer graphene and oxygen gas is below . Graphene combusts at . Graphene is commonly modified with oxygen- and nitrogen-containing functional groups"
"Hummers' method Hummers' method is a chemical process that can be used to generate graphite oxide through the addition of potassium permanganate to a solution of graphite, sodium nitrate, and sulfuric acid. It is commonly used by engineering and lab technicians as a reliable method of producing quantities of graphite oxide. It is also able to be revised in the creation of a one-molecule-thick version of the substance known as graphene oxide. Graphite oxide is a compound of carbon, oxygen, and hydrogen where there is a ratio between 2.1 and 2.9 of carbon to oxygen. Graphite oxide is typically a"
"under standard conditions, graphite is the most stable form of carbon. Therefore, it is used in thermochemistry as the standard state for defining the heat of formation of carbon compounds. Graphite conducts electricity, due to delocalization of the pi bond electrons above and below the planes of the carbon atoms. These electrons are free to move, so are able to conduct electricity. However, the electricity is only conducted along the plane of the layers. In diamond, all four outer electrons of each carbon atom are 'localised' between the atoms in covalent bonding. The movement of electrons is restricted and diamond"
"all proportional solid solution alloy of Pb and Bi has been synthesized in 2011. The supracrystals of 2D materials have been proposed and theoretically simulated. These monolayer crystals are built of supra atomic periodic structures where atoms in the nodes of the lattice are replaced by symmetric complexes. For example, in the hexagonal structure of graphene patterns of 4 or 6 carbon atoms would be arranged hexagonally instead of single atoms, as the repeating node in the unit cell. Graphane is a polymer of carbon and hydrogen with the formula unit where ""n"" is large. Graphane is a form of"
"Braggite Braggite is a sulfide mineral of platinum, palladium and nickel with chemical formula: (Pt, Pd, Ni)S. It is a dense (specific gravity of 10), steel grey, opaque mineral which crystallizes in the tetragonal crystal system. It is the central member in the platinum group end-members cooperite and vysotskite. It was first described in 1932 for an occurrence in the Bushveld Igneous Complex of South Africa. Its name came from William Henry Bragg (1862–1942) and his son, William Lawrence Bragg (1890–1971). It was the first mineral that was discovered with the assistance of X rays. It occurs as magmatic segregations"
"to the pore sizes. Research in transition metal decoration on carbon sorbents to enhance hydrogen binding energy has led to experiments with titanium and magnesium anchored to hydroxyl groups, allowing for the binding of multiple hydrogen molecules. Graphite oxide Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. The maximally oxidized bulk product is a yellow solid with C:O ratio between 2.1 and 2.9, that retains the layer structure of graphite but with a much larger and irregular spacing. The bulk material"
"dark graphite rich inclusions with the chiastolite crystals. Margarite Margarite is a calcium rich member of the mica group of the phyllosilicates with formula: CaAl(AlSi)O(OH). It forms white to pinkish or yellowish gray masses or thin laminae. It crystallizes in the monoclinic crystal system. It typically has a specific gravity of around 3 and a Mohs hardness of 4. It is translucent with perfect 010 cleavage and exhibits crystal twinning. It occurs commonly as an alteration product of corundum, andalusite and other aluminous minerals. It has been reported as forming alteration pseudomorphs of chiastolite along with muscovite and paragonite. The"
"material graphene."" ""Graphene"" is a combination of ""graphite"" and the suffix -ene, named by Hanns-Peter Boehm and colleagues, who produced and observed single-layer carbon foils in 1962. Boehm et al. introduced the term ""graphene"" in 1986 to describe single sheets of graphite. Graphene can be considered an ""infinite alternant"" (only six-member carbon ring) polycyclic aromatic hydrocarbon. The International Union of Pure and Applied Chemistry (IUPAC) notes, ""previously, descriptions such as graphite layers, carbon layers, or carbon sheets have been used for the term graphene...it is incorrect to use for a single layer a term which includes the term graphite, which"
"oxyacid salts, such as a basic selenate 2TeO·SeO and an analogous perchlorate and periodate 2TeO·HXO. Tellurium forms a polymeric, amphoteric, glass-forming oxide TeO. It is a ""conditional"" glass-forming oxide—it forms a glass with a very small amount of additive. Tellurium has an extensive organometallic chemistry (see Organotellurium chemistry). Carbon is ordinarily classified as a nonmetal but has some metallic properties and is occasionally classified as a metalloid. Hexagonal graphitic carbon (graphite) is the most thermodynamically stable allotrope of carbon under ambient conditions. It has a lustrous appearance and is a fairly good electrical conductor. Graphite has a layered structure. Each"
"and becomes what is known as pyrolytic carbon, a useful material in blood-contacting implants such as prosthetic heart valves. Graphite is the most stable allotrope of carbon. Contrary to popular belief, high-purity graphite does not readily burn, even at elevated temperatures. For this reason, it is used in nuclear reactors and for high-temperature crucibles for melting metals. At very high temperatures and pressures (roughly 2000 °C and 5 GPa), it can be transformed into diamond. Natural and crystalline graphites are not often used in pure form as structural materials due to their shear-planes, brittleness and inconsistent mechanical properties. In its"
"units. Graphite and the mica group of silicate minerals structurally consist of continuous two-dimensional sheets covalently bonded within the layer, with other bond types holding the layers together. Disordered network solids are termed glasses. These are typically formed on rapid cooling of melts so that little time is left for atomic ordering to occur. Network covalent bonding A network solid or covalent network solid is a chemical compound (or element) in which the atoms are bonded by covalent bonds in a continuous network extending throughout the material. In a network solid there are no individual molecules, and the entire crystal"
"physics, the main focus is currently on designing nanoelectronic components by the use of graphene as electrical conductor, hexagonal boron nitride as electrical insulator, and a transition metal dichalcogenide as semiconductor. Graphene's two surfaces are single sheets of carbon atoms arranged in a hexagonal honeycomb lattice. Having two surfaces and lacking bulk makes it the thinnest possible material but also 5 times stronger than steel due to pi and sigma orbital bonds. Graphene has high electron mobility and high thermal conductivity. Although graphene can be used in different applications, one issue regarding graphene is its lack of a band gap,"
"Gabrielite Gabrielite is a rare thallium sulfosalt mineral with a chemical formula of TlAgCu(As,Sb)S or TlAgCuAsS. It was first reported in 2002 for its occurrence in the Lengenbach quarry, Binntal, Valais, Switzerland, and named after Walter Gabriel (born 1943), a Swiss mineral photographer. This region was transformed during the greenschist-garnet/amphibolite facies of metamorphism. Due to this many rare sulfosalts like gabrielite are found in this part of Switzerland. Gabrielite has a pseudohexagonal shape and the crystal structure is composed of parallel sheets of ditriagonalization of hexagons which reduces it to a P3 symmetry. According to the American Mineralogist, Gabrielite shows"
"on early F-117 Nighthawk stealth strike fighters. Graphite composites are used as absorber for high-energy particles (e.g. in the LHC beam dump). Graphite is mined by both open pit and underground methods. Graphite usually needs beneficiation. This may be carried out by hand-picking the pieces of gangue (rock) and hand-screening the product or by crushing the rock and floating out the graphite. Beneficiation by flotation encounters the difficulty that graphite is very soft and ""marks"" (coats) the particles of gangue. This makes the ""marked"" gangue particles float off with the graphite, yielding impure concentrate. There are two ways of obtaining"
"Germanium dioxide Germanium dioxide, also called germanium oxide, germania, and salt of germanium, is an inorganic compound with the chemical formula GeO. It is the main commercial source of germanium. It also forms as a passivation layer on pure germanium in contact with atmospheric oxygen. The two predominant polymorphs of GeO are hexagonal and tetragonal. Hexagonal GeO has the same structure as β-quartz, with germanium having coordination number 4. Tetragonal GeO (the mineral argutite) has the rutile-like structure seen in stishovite. In this motif, germanium has the coordination number 6. An amorphous (glassy) form of GeO is similar to fused"
"Krotite Krotite is a natural mineral composed of calcium, aluminium and oxygen, with the molecular formula CaAlO. It is the low-pressure dimorph of CaAlO, of which the high-pressure dimorph is named dmitryivanovite. Krotite was reported in 2011 in a calcium-aluminium-rich inclusion (CAI) in the carbonaceous chondrite meteorite NWA (North West Africa) 1934, which landed in Morocco. The mineral name was approved by the International Mineralogical Association (IMA 2010-038) and honors Alexander N. Krot, a researcher in cosmochemistry at the University of Hawaii at Manoa in Honolulu, Hawaii. Researchers have found that the mineral, which has the same atomic arrangement as"
"in igneous rocks and in meteorites. Minerals associated with graphite include quartz, calcite, micas and tourmaline. The principle export sources of mined graphite are in order of tonnage: China, Mexico, Canada, Brazil, and Madagascar. In meteorites, graphite occurs with troilite and silicate minerals. Small graphitic crystals in meteoritic iron are called cliftonite. Some microscopic grains have distinctive isotopic compositions, indicating that they were formed before the Solar system. They are one of about 12 known types of mineral that predate the Solar System and have also been detected in molecular clouds. These minerals were formed in the ejecta when supernovae"
"Margarite Margarite is a calcium rich member of the mica group of the phyllosilicates with formula: CaAl(AlSi)O(OH). It forms white to pinkish or yellowish gray masses or thin laminae. It crystallizes in the monoclinic crystal system. It typically has a specific gravity of around 3 and a Mohs hardness of 4. It is translucent with perfect 010 cleavage and exhibits crystal twinning. It occurs commonly as an alteration product of corundum, andalusite and other aluminous minerals. It has been reported as forming alteration pseudomorphs of chiastolite along with muscovite and paragonite. The margarite in this occurrence forms preferentially along the"
"Hummers graphite oxides are also remarkably different. Recently a mixture of HSO and KMnO has been used to cut open carbon nanotubes lengthwise, resulting in microscopic flat ribbons of graphene, a few atoms wide, with the edges ""capped"" by oxygen atoms (=O) or hydroxyl groups (-OH). Graphite (Graphene) oxide (GO) has also been prepared by using a ""bottom-up"" synthesis method (Tang-Lau method) in which the sole source is glucose, the process is safer, simpler, and more environmentally friendly compared to traditionally “top-down” method, in which strong oxidizers are involved. Another important advantage of Tang-Lau method is control of thickness, ranging"
"crystals.) Cryptohalite has the cubic (isometric) crystal structure and corresponds to the alpha form. Both minerals have the chemical formula (NH)SiF. The halides of form ""ABX"" fall into two groups: hieratite and malladrite. The hieratite group is isometric whereas the malladrite is hexagonal. The (SiF) is octahedral—one fluorine atom at each vertex. In bararite, the (NH)’s are trigonally coordinated. They all appear at sites of C (3m) symmetry. The (NH) has 12 fluorine neighbors, which form four triangles. Three of these triangles are isosceles. These triangles themselves form a triangle—around the 3-fold axis containing the nitrogen atom. One triangle is"
"this circumstance, the stable structure of potassium graphite is an important advantage. Graphite intercalation compound Graphite intercalation compounds (GICs) are complex materials having a formula CX where the ion X or X is inserted (intercalated) between the oppositely charged carbon layers. Typically m is much less than 1. These materials are deeply colored solids that exhibit a range of electrical and redox properties of potential applications. These materials are prepared by treating graphite with a strong oxidant or a strong reducing agent: The reaction is reversible. The host (graphite) and the guest X interact by charge transfer. An analogous process"